Charge coupled device (CCD) or complementary metal oxide semiconductor (CMOS) sensors and the like are practically used as a solid-state imaging device. In such a solid-state imaging device, a plurality of pixels are arranged in a matrix shape.
In a portion of the semiconductor substrate layer corresponding to a single pixel, a predetermined number of portions using an impurity diffusion layer are arranged in appropriate positions. As the CCD, a structure in which an impurity diffusion layer that forms a perpendicular transmission portion is arranged under a transmission electrode, and an impurity diffusion layer that forms a photoelectric conversion portion is arranged between the transmission electrodes is known (for example, refer to JP-A-2006-228762, FIG. 1). In this related art, the relative positions of the perpendicular transmission portion and the photoelectric conversion portion to the transmission electrode are accurately set through self-alignment.
Self-alignment refers to a process of forming the impurity diffusion layer with respect to the layer formed over the semiconductor substrate by performing ion implantation after a layer that blocks ions, such as an electrode layer or a cover layer, is formed over the semiconductor substrate in advance. Through self-alignment, it is possible to accurately determine a relative position between the impurity diffusion layers with respect to the edges of the layers formed over the semiconductor substrate.